Generating Compilers for Qubit Mapping and Routing

TL;DR

This paper introduces a method to automatically generate quantum circuit compilers for qubit mapping and routing, adaptable to diverse hardware configurations, improving efficiency and solution quality over traditional handcrafted solutions.

Contribution

The paper presents a novel approach to automatically generate QMR compilers using a common core structure and a domain-specific language, applicable to any quantum processor.

Findings

Generated compilers are competitive with handwritten ones in runtime.

Solution quality of generated compilers matches specialized solutions.

Approach is adaptable to diverse and evolving quantum hardware.

Abstract

To evaluate a quantum circuit on a quantum processor, one must find a mapping from circuit qubits to processor qubits and plan the instruction execution while satisfying the processor's constraints. This is known as the qubit mapping and routing (QMR) problem. High-quality QMR solutions are key to maximizing the utility of scarce quantum resources and minimizing the probability of logical errors affecting computation. The challenge is that the landscape of quantum processors is incredibly diverse and fast-evolving. Given this diversity, dozens of papers have addressed the QMR problem for different qubit hardware, connectivity constraints, and quantum error correction schemes by a developing a new algorithm for a particular context. We present an alternative approach: automatically generating qubit mapping and routing compilers for arbitrary quantum processors. Though each QMR problem is different, we identify a common core structure-device state machine-that we use to formulate an abstract QMR problem. Our formulation naturally leads to a compact domain-specific language for specifying QMR problems and a powerful parametric algorithm that can be instantiated for any QMR specification. Our thorough evaluation on case studies of important QMR problems shows that generated compilers are competitive with handwritten, specialized compilers in terms of runtime and solution quality.